It is suggested that it is possible to define an equivalent electric charge for an intense laser pulse (which can be described as a photon bunch) propagating in a plasma. It is also shown that this equivalent charge can be a source of new radiation processes in an inhomogeneous plasma. The results are extended to the case of a neutrino bunch, which is coupled to the plasma by weak nuclear forces.
Mendonça, J. T., Oliveira e Silva, L., Bingham, R., Tsintsadze, N. L., Shukla, P. K., & Dawson, J. M. (1998). Equivalent charge of photons and neutrinos in a plasma. Physics Letters A, 239(6), 373-377. https://doi.org/10.1016/S0375-9601(98)00055-3